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Effects of rugby sevens matches on human neutrophil-related non-specific immunity
  1. I Takahashi1,
  2. T Umeda1,
  3. T Mashiko2,
  4. D Chinda1,
  5. T Oyama1,
  6. K Sugawara1,
  7. S Nakaji1
  1. 1Department of Social Medicine, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan
  2. 2Department of Physical Fitness and Health, National Defense Medical School, Tokorozawa, Saitama, Japan
  1. Correspondence to:
 Dr Shigeyuki Nakaji
 Department of Social Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, 036-8562, Aomori, Japan; nakaji{at}


Aims: To evaluate the influences of the accumulative effect of two consecutive rugby sevens matches (Sevens) on aspects of human neutrophil-related non-specific immunity.

Methods: In seven players participating in the Japan Sevens, neutrophil reactive oxygen species (ROS) production capability and phagocytic activity were measured using flow cytometry, and serum opsonic activity (SOA) was assessed by measuring neutrophil ROS using the peak height of lucigenin-dependent chemiluminescence before and after two consecutive matches.

Results: ROS showed no change immediately after the first match, and had significantly (P<0.05) increased 4 h later, but showed a decrease after the second match. Phagocytic activity showed no change immediately after the first match, but had significantly (P<0.01) decreased 4 h later, and showed a further decrease after the second match, although it was not significant. SOA significantly (P<0.01) increased after the first match, and still maintained its high 4 h later, but decreased after the second match. ROS production capability, phagocytic activity and SOA significantly (P<0.01) decreased after the second match.

Conclusions: When rugby players play two consecutive Sevens matches, the exercise loading is thought to be hard, similar to that experienced during a marathon race and intensive or long training in a training camp, although the expected changes were not seen after the first match. Differences between after the first and the second matches may be due to the “cumulative effect”.

  • ALT, alanine aminotransferase
  • AST, asparate aminotransferase
  • FITC, flouorescein isothiocyanate
  • LDH, lactate dehydrogenase
  • ROS, reactive oxygen species
  • SOA, serum opsonic activity

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  • Published Online First 11 October 2006

  • Funding: This work was supported by a grant-in-aid for scientific research from the Ministry of Education, Science and Culture of Japan (Number 11470092).

  • Competing interests: None declared.